Question: If $a + b + c = -7$ and $x + y = -1$, what is $-10b + 5y - 10c + 5x - 10a$ ?
Answer: $= -10a - 10b - 10c + 5x + 5y$ $= (-10) \cdot (a + b + c) + (5) \cdot (x + y)$ $= (-10) \cdot (-7) + (5) \cdot (-1)$ $= 70 - 5$ $= 65$